AICE Biology - Chapter 5 Review

Topic: The Mitotic Cell Cycle

How do organisms grow?

Through cell division (mitosis), not by making bigger cells.

All cells are ____

small.

Why is it advantageous for cells to have a smaller size?

* it is easier/faster for substances to be moved into or our of the cell by diffusion.
* it is easier for he genes/chromosomes to control metabolic functions.
* there can be more cell specialization and a greater variety of functions

What are the types of mitosis?

* mitosis
* meiosis

Why does mitosis happen?

* Growth
* Tissue repair/replacement, and in some organisms, for asexual reproduction.
* Immunity response and make cells that fight off infractions (cloning).

When/where does meiosis occur?

* For the production of gametes (sex cells or reproductive cells) used in sexual reproduction.
* Takes place in the cells of the testicles (spermatocytes) or the ovaries (oocytes), producing sperm cells in males and ova in females.

Has all chromosomes (2n)

Diploid

Has half chromosomes (n)

Haploid

A disease in which cells divide out of control

Cancer

Cancer is a disease of the ___

cell cycle

Risk factors of cancer

* exposure to radiation (radioactive substances) or too much ultraviolet radiation (UV light) from the sun.
* exposure to carcinogens (toxic chemicals or substances that cause cancer), such as tobacco, tar, asbestos, and benzene.
* genetic predisposition (so it may happen spontaneously) because of family history of active oncogenes (the genes that cause cancer).
* some viruses, such as HPV, Hepatitis B virus, some forms of Herpes virus, and Epstein-Barr virus.

What process does cancer go through to spread?

Metastasis

When cancer cells break out of a tumor and spread to other parts of the body, causing secondary tumors.

Metastasis

Differences between mitosis and meiosis

* ==mitosis has one cell division while meiosis has two consecutive cell divisions==

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* ==in mitosis two daughter cells are produced while in meiosis four daughter cells are produced==

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* ==daughter cells are identical to each other and the parents in mitosis while genetically unique to each other and the parent in meiosis.==

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* ==in mitosis the daughter cells are diploid while in meiosis they are haploid.==

Asexual Reproduction

* ==Does not involve the use of gametes==
* Provides a lot of offspring **(main advantage)**
* ==Only one parent is involved==
* Results in very little or no genetic variation in a population **(main disadvantage)**

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Sexual Reproduction

* ==involves gametes (sex cells/reproductive cells, which are the sperm cells and ova)==
* ==two parents are involved (male and female)==
* results in a great deal of genetic variation within a population **(main advantage)**
* produces fewer offspring **(main disadvantage)**

Describe the Cell Cycle

Interphase divided into 3 stages: G1, S, and G2 stages. M phase (cell division) follows interphase.

Proteins that contribute to the cell cycle by regulating it/they control the cell cycle

Cyclin

Rapidly Dividing Cells

Skin cells, Epithelial cells (digestive track lining), Hair follies, and nails.

G0 phase

When the cells will never ever divide again. Some stop dividing early and some stop later.

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Ex: nerve cells, skeletal muscle cells, adipose cells (fat cells)

G1 phase (Greatest cell growth)

Cellular contents, excluding the chromosomes, are duplicated. this is the stage of greatest cell growth and replication of organelles.

S phase: DNA replication

Each of the 46 chromosomes is duplicated by the cell. this is the stage in which DNA is replicated.

G2 phase (shortest stage): preparing for cell division

The cell “double checks” the duplicated chromosomes for error, making any needed repairs.

M phase: cell division

This stage follows interphase and produces two daughter cells

In eukaryotes, cell division occurs in…

two main stages.

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The first stage is the process of division of the cell nucleus (mitosis) and the second stage is the division of the cytoplasm (cytokinesis).

Mitosis phases

prophase, metaphase, anaphase, telophase, and interphase.

The genetic material inside the nucleus condenses and the duplicated chromosomes become visible.

Prophase

A fanlike system of microtubules that will help to separate the duplicated chromosomes.

Spindle

The centromeres of the duplicated chromosomes line up across the center of the cell, spindle fibers connect the centromere of each chromosomes to the two poles of the spindle.

Metaphase

When the chromosomes separate and move along spindle fibers to opposite ends of the cell.

Anaphase

The chromosomes, which were distinct and condensed, begin to spread out into a tangle of chromatin

Telophase

Cytokinesis

Completes the process of the cell division, it splits one cell into two.

Animal Cells - Cytokinesis

The cell membrane is drawn inward until the cytoplasm is pinched into two nearly equal parts in the centriole

Plant Cells - Cytokinesis

The cell membrane is not flexible enough to draw inward because of the rigid cell wall that surrounds it. instead, a structure known as the cell plate forms halfway between the divided nuclei.

Why is it incorrect to call interphase a resting phase?

Interphase does not describe a cell that is resting. rather, the cell is living and preparing for later cell division through the G1, S, and G2 phase.

What does each chromosome consist of?

two identical sister chromatids

Each pair of chromatids is attached to an area called the…

centromere

What are the two tiny structures located in the cytoplasm near the nuclear envelope at the beginning of prophase?

centrioles

a group of proteins stimulating the growth of specific tissues.

Growth factors

The division of a cell’s cytoplasm

Cytokinesis

The final phase of mitosis is

telophase

The phase of mitosis in which microtubules connect the centromere of each chromosome to the poles of the single is

metaphase

At the beginning of cell division, each chromosome consists of two sister ____

chromatids

The longest phase of mitosis is ___

prophase

The phase of mitosis that ends when the chromosomes stop moving is

anaphase

The process by which a cell divides into two daughter cells is called __

cell division

A tiny structure located in the cytoplasm near the nuclear envelope is a ___

centriole

A disorder in which some of the body’s cells lose the ability to control growth

Cancer

The area where a pair of chromatids is attached

Centromere

The devision of the cell nucleus is called

mitosis

A protein that regulates the timing of the cell cycle in eukaryotic cells is

cyclin

The series of events that cells go through as they grow and divide is known as the

cell cycle

A fanlike microtubule structure that helps separate the chromosomes is a

spindle

The time period between cell divisions is called

interphase

Cancer cells don’t respond to signals that regulate…

growth

Cancer cells form masses of cells called __

tumors

Cancer cells break loose and spread throughout the…

body

How do cells growing bigger represent a problem in the transport of substances?

If a cell were to get too large, it would be more difficult to get sufficient amounts of oxygen and nutrients in and waste products out

How do cells growing bigger represent a problem to the function of the cell’s DNA?

As cells grow, DNA is used to build the molecules needed for cell growth. However, as the cell grows, the DNA remains the same size.

Which organisms are able to reproduce asexually?

For many single-celled organisms, cell division is the only form of reproduction. however, asexual reproduction can also occur in many multicellular organisms.

Which organisms are able to reproduce sexually?

Most animals and plants reproduce sexually, as do many single-celled organisms.

Explain the relationship between DNA, chromosomes, and chromatin.

Genetic information is bounded into packages of DNA known as chromosomes. DNA tightly bound to proteins (histones) are chromatin.

Describe the characteristics of chromosomes in prokaryotes.

Most prokaryotes contain a single circular DNA chromosome. This chromosome contains nearly all of the cell’s genetic information.

Describe the characteristics of chromosomes in eukaryotes.

Eukaryotes contain multiple chromosomes because they have more DNA. The chromosomes in eukaryotic cells contain DNA tightly bound to proteins known as histones.

How is the cell cycle in prokaryotes?

The process of cell division in prokaryotes is binary fission (a form of sexual reproduction).

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Once the chromosome has been replicated, the two DNA molecules are attached to different regions of the cell membrane. A network of fibers forms between them that constrict and the cell is pinched inward. This divides the cytoplasm and chromosomes into two nearly genetically identical cells.

How is the cell cycle in eukaryotes?

the eukaryotic cell cycle consists of four stages: G1, S, G2, and M. the length of each stage of the cell cycle - and the length at the entire cell cycle - varies depending on the type of cell.

How is cytokinesis and mitosis different in animal and plant cells?

* Mitosis: animals have centrioles to form spindle fibers while plant cells do not. plant cells make spindle fiber from Golgi apparatus.

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* Cytokinesis: plant cells build a cell wall/cell plate. animal cells pinch in to form a cleavage furrow.

Cancer cells make their own…

Growth factors which causes uncontrollable cell division.

Why are cyclings called internal regulatory proteins?

They respond to events inside the cell.

Why are growth factors called external regulatory proteins?

They are especially important during embryonic development and wound healing.

Explain, what is apoptosis, and how does it happen?

Apoptosis is a process of programmed cell death. When it is triggered, a cell undergoes a series of controlled steps leading to its self-destruction.

Why is apoptosis important in an organisms development?

Apoptosis is important in an organisms development because it plays a key role in growth by shaping the structure of tissues and organs. When apoptosis does not occur as it should, a number of diseases can result such as AIDS and Pakinsans disease.

What is the difference between a benign tumor and a malignant tumor?

A bengin tumors is noncancerous and does not spread to surrounding healthy tissues or to other parts of the body. Malignant tumors are cancerous and invade/destroy surrounding healthy tissue.

List 4 factors that may cause the risk of getting cancer.

1. smoking or chewing tobacco
2. radiation exposure
3. vital infection
4. damaged or defective p53 genes

Which are the three most common treatments for cancer? List the advantages and disadvantages of each one of those treatments.

* one treatment for curing cancer is removing it by surgery. an advantage of this method is that it can be fast and easy. a disadvantage is that it can only be used for localized cancer.
* a second treatment for curing cancer is beams of radiation. an advantage is that cancer cells are especially vulnerable to damage from high-energy radiation. a disadvantage is that the beams of radiation have to be carefully targeted.
* a third treatment for curing cancer is chemotherapy. an advantage is that it cures some forms of cancer. a disadvantage is that it also interferes with cell division in normal, healthy cells.

What are specialized cells, and the process of differentiation?

* Specialized cells have a specific function, such as muscle cells or nerve cells. embryo. differentiation is the process by which cells become specialized.

Unspecialized cells from which differentiated cells develop

Stem cells

What is the difference between embryonic stem cells and adult stem cells?

Adult stem cells produce the new cells needed for the tissues in which they are found. Embryonic stem cells, however, are more versatile than adult stem cells,

What is the importance of stem cell research?

Stem cells can be used right after an incident to replenish non-dividing cells. younger people can heal from incidents that damage cells faster then adults because their cells can make new ones.

What ethical issues and problems have come up from the use of stem cells in research?

* Adult stem cells are harvested from a willing donor, which brings up ethical issues.
* Embryonic cells are generally obtained in ways that cause the destruction of an embryo. human embryonic stem cells research is controversial because the arguments for it and against it both involve ethical issues of life and death.

How have some of those problems been solved?

iPS cells have been developed to address ethical issues.

*These cells may be able to replace embryonic stem cells.*

When the zygote is able to develop into any type of cell in the body

Totipotent

A hollow ball of cells within a cluster of cells inside down as the inner cell mass, forms after about four days of development

Blastocyst

A cell that is able to develop into many different types of cells or tissues in the body

Pluripotent

Cells can develop into more than one cell type

Multipotent

What is the potential use of stem cells in future medicine?

* Regenerative medicine makes use of stem cells to repair or replace damaged cells and tissues.
* Researchers have also developed new laboratory “recipes” that can make cells into certain other cell types.
* Macular degeneration

The G in G1 and G2 stands for…

gap.

The S in S phase stands for…

synthesis.

What is the longest phase in mitosis?

Prophase

What is the shortest phase in mitosis?

Metaphase

When you can’t see the chromosomes

In interphase, not dividing

DNA tightly bound to proteins

Histones

1 chromosome, 1 chromatid, when it duplicates becomes….

A sister chromatid, 1 chromosome, 2 chromatids

When chromatids are attached to centromere…

They are considered one chromosomes

When chromatids are detached…

They are considered two individual chromosomes, count by number of chromatids

polar bodies, do nothing; genetically the same

Ococyte

The first cell to form when we are conceived, start to divide due to mitosis

Zygotes

egg and sperm cells in sexual reproduction

Gametes

a long DNA strand with tightly packed proteins (histones)

Chromosomes

Replicated DNA, identical

Chromatid